( Qs. [Jan., 
II. ON THE MECHANICAL PROPERTIES OF IRON 
AND STEEL. 
By W. Farrzarrn, F.BS. 
Henry Bessemer, like his prototype, Cort, has effected a revolution 
in the manufacture of iron and steel; and the present improvements 
exhibit a means of development by which the former will ultimately 
double its strength, and in the state of steel be substituted for 
purposes of construction. The result of this change, when applied 
to structural purposes, is considerable, as half the weight of steel 
is equal in strength, and consequently is cheaper than a given 
weight of iron. In almost every case where iron is at present 
used, steel would then be employed: as in the construction of 
bridges, ships, and other structures to which iron is now applied. 
It only requires certainty and uniformity of character in its manu- 
facture, to ensure its superiority and extend its application. This 
has not as yet been accomplished; but the Bessemer process, by 
depriving the crude metal of its carbon im a separate vessel, 
certainly tends in that direction; for by this process increased 
facilities are not only afforded, and new combinations formed, 
but the introduction of measured quantities of the same metal, 
containing the requisite quantity of carbon, poured into the con- 
verting vessel, appears to be the only true principle on which 
steel in its varied conditions of ductility, tenacity, &c., can be pro- 
duced. ‘These quantities, when duly proportioned, indicate the 
quality of the steel to be obtained from this process, and, when cast 
into ingots are ready either for the forge or the rolling-mill. From 
this it will be seen that every description of homogeneous iron or 
steel may be produced, care being taken to ascertain the exact 
percentage of carbon requisite to be infused in order to combine 
with the mass of refined metal. 
This process of conversion as adopted by Mr. Bessemer is en- 
tirely new, when compared with the old method employed in 
the converting furnace with the bars embedded in charcoal, which 
required at least a fortnight for the refined iron to absorb the 
necessary quantity of carbon to form steel. By the new system 
steel is produced in the Bessemer vessel in less than twenty minutes, 
whereby a great saving of time, fuel, and other expenses is effected. 
As this process is extremely interesting, it may be briefly described 
as follows :— 
A quantity of pig-iron, containing an average quantity of car- 
bon, say 5 per cent., is melted in one or more reverberatory furnaces, 
according to the size of the converting vessel to be used, which 
varies in capacity from five to ten or twelve tons. When the metal 
becomes fluid, it is run into the converting vessel, to which is 
